org.parboiled.Action Maven / Gradle / Ivy

Go to download
/*
 * Copyright (C) 2009-2011 Mathias Doenitz
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.parboiled;

import com.github.parboiled1.grappa.matchers.delegate.SequenceMatcher;

/**
 * Instances of classes implementing this interface can be used directly in a
 * rule definition to define a parser action.
 * If the class also implements the {@link ContextAware} interface it will be
 * used to inform the object of the current parsing {@link Context} immediately
 * before the invocation of the {@link #run} method.
 * Additionally, if the class implementing this interface is an inner class
 * (anonymous or not) and its outer class(es) implement(s) {@link ContextAware}
 * its outer class(es) will also be informed object of the current parsing
 * {@link Context} immediately before the invocation of the action's {@link
 * #run} method.
 * This allows simple anonymous action class implementations directly in the
 * parser rule definitions, even when they access context-sensitive methods
 * defined in the BaseActions or BaseParser classes.
 *
 * NOTE! IMPORTANT! Right now there is a severe limitation
 * that an {@code Action} instance, if it is to collect a value, must be the
 * second or later rule of a {@link SequenceMatcher}. This limitation will be
 * removed in the future.
 *
 * @see BaseActions#match()
 */
public interface Action
{
    /**
     * Runs the parser action.
     *
     * @param context the current parsing context
     * @return true if the parsing process is to proceed, false if the current
     * rule is to fail
     */
    boolean run(Context context);
}